The liquid crystal display device, especially the Thin Film Transistor Liquid Crystal Display (TFT-LCD) has been widely used in computers, flat televisions, mobile phones and other information products due to its outstanding performance. During design and production of liquid crystal display panel, how to avoid the color shift phenomenon is an important challenge faced by the Research & Development personnel. The color shift phenomenon means that the colors displayed in an image containing multiple colors are non-uniform when the image is presented, and the image would contain more ingredients of a certain color. For example, when an image with the yellow color as a whole is presented, some areas would look red. There are many reasons for the color shift phenomenon of the liquid crystal display device. For instance, the poor quality of the video signal lines (data lines) or the poor contact thereof would result in serious color shift problems.
The present disclosure mainly discusses the color shift problem resulted from the delay effect of the data wirings. In the liquid crystal display panel, pixel units are arranged on an array substrate in a form of a matrix array, and a data driving module outputs data signal voltages representing the image information to the pixel units through data lines. A pixel electrode of each pixel unit is charged with a corresponding electric potential according to the data signal voltage transmitted from the data line, and the charging effect thereof can be measured by a charge rate. In this case, the pixel electrode drives corresponding liquid crystal molecules to deflect, whereby light can transmit, so that the image information can be presented. Since the data wirings have a certain impedance, which is equivalent to an RC network in series connection, a certain delay distortion must occur to the data signal voltage during transmission, and thus the electric potential of the pixel electrode of the pixel unit cannot completely reach an electric potential of the data signal voltage output by the data driving module. In general, the larger the equivalent resistance value and capacitance value of the data wirings are, the lower the charge rate of the pixel electrode would become if other factors are not taken into consideration. In addition, in the liquid crystal display device, since the liquid crystal molecules are generally driven by alternating current, an inversion between high-level voltage and low-level voltage exists in the data signal voltage output to the pixel unit by the data driving module. During this procedure, a waveform of the data signal voltage of the pixel electrodes in an upper row of the active area is better than a waveform of the data signal voltage of the pixel electrodes in a lower row of the active area due to the delay effect of the data wirings (as shown in FIG. 1). In this case, the charge rate of the pixel units in the upper row is higher than that of the pixel units in the lower row, and thus the brightness of the pixel units in the upper row is higher than that of the pixel units in the lower row.
In a word, the charge rates of the pixel units in different regions of the active area of the liquid crystal display panel would be different due to the delay effect of the wirings, and thus the degrees of brightness, the picture contrasts, and the color mixture effects of the pixel units in different regions are all different. In particular, when the impedance of the data lines in a right side and a left side of the liquid crystal display panel is far different from that of the data lines in a central part of the liquid crystal display panel, the serious color shift phenomenon as described hereinabove would occur.